RadioLib: LoRaWan - Raspberry Pi 3B error -6 on method LoRaWANNode::sendReceive()

Hi!

Im using Raspberry Pi 3B to transmit LoRaWAN messages but im getting the error -6 on method sendReceive(). The module im using is the SX1272.

Pinout: NSS pin: 8 DIO0 pin: 17 DIO1 pin: 13 RST pin: 4

The following code is:

#include <RadioLib.h>
#include "PiHal.h"
#include <string>
#include <stdio.h>


PiHal* hal = new PiHal(1);

SX1272 radio = new Module(hal, 8, 17, 4, 13);

LoRaWANNode node(&radio, &US915, 2);

uint32_t devAddr = 0x2******3;

uint64_t devEUI = 0x2**************3;

uint8_t nwkKey[] = { 0x2B, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0x3C };

uint8_t appKey[] = { 0x2B, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0x3C };

int beginRadio(SX1272 radio){
  int state = radio.begin();
  if(state == RADIOLIB_ERR_NONE){
    printf("[Radio Begin]...ok!\n");
    return (state);
  } else {
    printf("[Radio Begin]...error: %i\n",state);
    return (-1);
  }
}


int beginABPLora(){
  int state = node.beginABP(devAddr, nwkKey, appKey);
  if(state >= RADIOLIB_ERR_NONE){
    printf("[LoRa ABP Begin]...ok!\n");
    return(state);
  } else{
    printf("[LoRa ABP Begin]...error: %i\n",state);
    return (-1);
  }
}
int main(){
  printf("[Radio]...ok!\n");
  printf("[LoRa Node]...ok!\n");

  int state = beginRadio(radio);
  state = beginABPLora();

  // node.setADR(true);
  // node.setDutyCycle(true, 1250);
  // node.setDwellTime(true, 1000);
  
  uint8_t count = 0;
  while(true){
    const char *strUp = "hello!";
    uint8_t strDown[256];
    size_t lenDown = 0;
    uint8_t port = 10;
    int16_t state = node.sendReceive(strUp, port, strDown, &lenDown);
    // int16_t state = node.uplink(strUp, port);
    if(state == RADIOLIB_ERR_NONE){
      printf("[LoRa sendReceive]...ok!\n");
      printf("[LoRaWAN] Data:\t\t");
      size_t dataDownLength = sizeof(strDown) / sizeof(strDown[0]);

      if(dataDownLength > 0){
        printf("%s",strDown);
      } else {
        printf("<MAC commands only>");
      }
    } else{
      printf("[LoRa sendReceive]...error: %i\n",state);
      return (-1);
    }

    uint32_t minimunDelay = 60000;
    uint32_t interval = node.timeUntilUplink();
    uint32_t delayMs = std::max(interval,minimunDelay);
    hal->delay(delayMs);
  }
  return(0);
}

The error im getting:

[Radio]...ok!
[LoRa Node]...ok!
[Radio Begin]...ok!
[LoRa ABP Begin]...ok!
[LoRa sendReceive]...error: -6

Additional information:

• Library version 6.4.2